


Puzzle You Out

by Self_Indulgent_TMNT



Category: Teenage Mutant Ninja Turtles (TV 2012), Teenage Mutant Ninja Turtles - All Media Types
Genre: F/M, Reader-Insert, Scientist Reader, genius reader
Language: English
Status: Completed
Published: 2017-12-23
Updated: 2017-12-23
Packaged: 2018-09-23 21:23:21
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 9
Words: 7,362
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9678398
Author URL: https://archiveofourown.org/users/Self_Indulgent_TMNT/pseuds/Self_Indulgent_TMNT
Summary: A mutual love of science brings Donnie and Y/N together, but despite the incredible sceintific problems they can solve together there is one mystery she'll never let him find the answer to. She reamins an enigma, the one problem he will never solve, but he will never stop trying.DISCLAIMER: I am not of a scientific mind, I have no idea about this stuff so I will mainly be making stuff up and being vague. The science isn't really the point of this.





	1. Meetings

When the teenage mutant ninja turtles broke into a laboratory to use a super sophisticated piece of equipment one night it was because they thought they’d find the lab empty. Donnie needed to analyse some mutant DNA which he thought my hold the key to create a far more effective, easily synthesised retromutagen and his equipment just wasn’t advanced enough to do the tests he needed. There wouldn’t be anyone there at 2am he’d reasoned, the lab didn’t carry out long-term experiments that might need observing through the night so everyone would have gone home. Sound logic.  
So the brothers hacked the door and slipped inside, having sent a power surge through the CCTV cameras to overload them. Once inside, they searched through the labs until Donnie found the room he needed. He inserted his sample into the machine and began working as the boys grew more comfortable, confident they were safe and alone.  
Unbeknownst to them, they weren’t alone. A couple of rooms away Y/N, a young research assistant, was bent over a microscope, sipping strong coffee in an attempt to stay awake. The room was lit only by a desk lamp as she worked through the night, taking advantage of the empty labs to run her own experiments in secret. Y/N dripped the tiniest amount of her newest concoction onto the small sample of plant matter on her microscope slide, desperately hoping that this time it would have the required results. She held her breath in anticipation as the vaguely blue liquid soaked into the leaf and nothing happened for a moment. Then, after a couple of seconds, the leaf turned a disappointing shade of brown as it lost all possible regenerative properties it might have once contained.  
“Damn it!”  
Y/N pushed her wheelie chair away from the desk and rolled across the floor in frustration. This was not the result she had wanted. She sat in the darkness, silently spinning for a moment as she reflected upon her failure. Her self-pity was interrupted, however, by the sound of voices a few rooms away. There was definitely not supposed to be anyone else here, even she wasn’t supposed to be here.  
Y/N grabbed her failed mixture, she’d just accidentally proven that it killed cells so it would make a pretty decent weapon, and slipped out of the lab, trying to make as little noise as possible as she quietly made her way to the lab two down from hers. Pausing outside the door she took a breath, collecting herself before running in, beaker of liquid held threateningly above her head. When she saw the intruders, she froze in fear. Before her were four giant turtle mutants, all very much armed.  
“Donnie, I thought you said this place was empty” Leo muttered to his brother, who was sat at the computer.  
“It’s supposed to be” Donnie replied.  
“Oh my god” Y/N muttered “Oh god”  
“Ma’am, it’s ok, we’re not gonna hurt you” Leo said, raising his hands in a gesture of peace.  
“I-I’m going to have to ask you to leave” she said, trying to make your voice sound strong and threatening.  
“Or you’ll hit us with a beaker” Raph said, eyeing the beaker of liquid quizzically.  
“I’ll have you know that this is incredibly dangerous stuff” you replied “although that wasn’t the original intention” you added, lowering the beaker and looking at it. Your eyes then fell on the computer screen, on the analysis the turtles appeared to be carrying out. Suddenly the situation seemed a lot more manageable. Mutants you couldn’t deal with, but science was a whole other matter.  
You put the beaker down, moving over to the computer. “There’s gotta be a faster way of doing that” you said, leaning down to look at the screen.  
“Excuse me?” Donnie asked, not quite following.  
“This analysis, you’re doing it the long way. This computer is far more advanced even than this, here if you do it this way…”, you started typing, bringing up a different programme and inserting a few lines of what looked like gibberish to the other three turtles but which made complete sense to Donatello.  
“That’s genius” he said, watching you pull sense out of the chaos he’d expected to spend hours unravelling.  
You smiled modestly “Tell that to the guy who designed it, I just carry out the motions” you said, pulling up another chair. “What on earth is this stuff?”  
“A sample of a mutated Venus fly trap”  
“I am not even gonna ask about how you got that” you muttered, pulling the sample out of the machine and putting it under a microscope. “Why are you analysing it in my lab?”  
“Couldn’t do it at home” came the reply. You looked away from the microscope to eye the mutants up and down.  
“Yeah that makes sense, where are four turtle mutants gonna get advanced scientific equipment. I guess I’d do the same thing if I were you. Actually, I guess I am doing the same thing”  
“You are?” Leo asked.  
“I’m just a lab assistant here, I sneak in at night to run my own experiments. I’m Y/N by the way”  
“Donnie” Donnie said, then introduced his brothers one by one.  
“Pleasure to meet you. It’s good to see that the importance of science isn’t lost on mutants”  
“Yeah, that’s more Donnie’s department” Raph muttered.  
“I get science too” Mikey protested.  
“Sure you do, doofus”  
You downloaded the results of Donnie’s analysis onto the storage device he handed you, evidently made from parts of various broken ones. You admired it. “Did you do this? Fix up all these parts?” you asked him. Donnie smiled.  
“Yeah, I do what I can with what I have”  
That gave you an idea. “So if I gave you some busted stuff from the lab here, would you be able to find a use for it?”  
Donnie’s face lit up at the possibilities “Undoubtedly”  
You grinned. “Wait here” you said, running off to the lab’s rubbish, waiting to be picked up the next morning. Next to the sealed sacks of various chemical waste was a couple of pieces of tech which had broken. You’d thought it seemed a shame to throw them away, there was probably still something useful in there, but your boss had got angry when you questioned his instructions to dispose of them. You lugged them back to the turtles.  
“What do you think of these?” you asked, handing them over to Donnie.  
“You just made all his Christmases come at once” Leo said with a smile as Donnie gazed at the tech.  
“This is incredible, I’d never be able to get something like this” he said, looking at you with wide eyes “Thank you”  
“Don’t mention it, seemed a shame that they were just gonna get binned. I’m always happy to help a fellow scientist”  
You yawned and glanced at your phone. It was definitely past your bedtime. “Now if you’ll excuse me, I’m going home to bed. I’m sure you can see yourselves out” you said, walking out of the lab and heading for the door.


	2. A Thanks

**Summary for the Chapter:**

> This chapter is short but sweet

A couple of days after your encounter with the turtles, you received a small parcel from reception, apparently left on the desk that night with a note that said ‘for Y/N – the lab assistant’. You thanked the receptionist and took the parcel, slipping into your pocket until you reached the lab where you were working before taking it out again.

It was a small box tied with green ribbon. Inside was a necklace, a tiny pendant in the shape of a beaker, made out of polished glass with cracks as thin as a human hair creating a spider-web effect across the surface. It seemed to shimmer strangely in the light, refracting light off at odd angles so that it shone different colours. Underneath the necklace was a folded note that read:  
‘Thanks for your help.  
I found a use for everything, but this lens was cracked beyond repair, I hope it enjoys its new life as a necklace.  
D’


	3. She's Gonna Change The World

It was a couple of days since you received the parcel from Donnie and you’d slipped into the darkened lab in the middle of the night again. You were bent over a counter, humming to yourself while you carefully prepared your newly modified mixture, this time it had a slightly purple tint. This time it would work, or at least that’s what you told yourself as you dropped a small amount onto a leaf from the same plant you’d used last time. There was a brief pause then the leaf started foaming where the liquid had hit it. Once the foaming was done there was a perfectly circular hole in the leaf. The edges of the hole were slightly brighter green than the rest of the leaf, possible evidence of hastened growth, but that didn’t change the fact that your mixture had in fact burnt through the leaf.  
You sighed, resting your head on the desk. “Why do I even bother?” you asked the empty room.  
“Because one day you’ll make a breakthrough which changes the world” the room replied Your head shot up, looking towards the source of the sound. A couple of meters away, Donatello was sat on the desk.  
“Oh, Donnie, it’s you” you said, allowing yourself to relax again.  
“Yeah, it’s me” he replied, eyeing your failed experiment. You looked down at the leaf, now smouldering slightly.  
“You know, I’m starting to think I’m never going to work this out”  
“Don’t lose faith, you’ll get there” Don said with a smile, which you returned.  
“Thanks Donnie, and thanks for the necklace as well, it’s beautiful”  
He shrugged, cheeks turning red. You decided it would be best to move on. “What can I help you with, anyway”  
Donnie was instantly less awkward, now back in his comfort zone. “here” he said, producing a sheet of paper covered in numbers, symbols and squiggles. To most people, that piece of paper would have made no sense whatsoever, but to you it was poetry. You took one look at that mess of squiggles and it was like it told a story, or maybe choreographed a dance is a more accurate description, because those symbols meant movement and creation, describing the incredibly elegant nature of a very specific set of reactions. “Wow…” you breathed, “Donnie, this is really complex stuff”  
“Yeah, too complicated as it turns out. I can’t quite seem to get all of my equations to line up, and if my calculations are wrong then I might as well abandon this project. I was hoping you’d take a look at it, maybe a fresh pair of eyes will help”  
“I can certainly take a look, no guarantees though, this is way beyond my level”  
“Thanks, I appreciate it”  
Donnie took a seat while you took a closer look at his notes, scribbling notes in the margins to try and keep track of it all. His eyes fell to the failed experiment on the counter. You were completely distracted by his problem, muttering to yourself in a way that made him smile, and so he went unnoticed when he picked up your research folder. Inside, he found months of work – notes, photos, diagrams. Your folder tracked the progress of your late-night experiments from the very beginning, from the very first leaf, which you’d dissolved entirely. Donnie was impressed, there was evidence of incredible intellect in that folder, a really solid theory. You were still going through his notes, so he leant over and picked up your latest failure, not noticing the massive hole in the leaf so much as the tiny flecks of bright green on its edges, clear signs of cell regeneration in the otherwise dead leaf. Donnie smiled to himself, this was a girl who was going to change the world.  
He put down the leaf and turned to look at you, marvelling at how your innocent research assistant exterior could hide a brain as powerful as yours clearly was. As he thought this, your brow seemed to unfurrow and your face cleared. A few seconds of frantic scribbling followed, and then a whoop of glee. “Got it!” you cried, excitedly circling an area of circles about half way down the page and writing in your correction next to it.  
Donnie took the notes back and read through your correction. It seemed so simple now it was pointed out, but the original mistake was so small that he doubted he would ever have noticed it. “That’s brilliant, Y/N” he said, turning to you with an awed grin. You blushed.  
“Thanks”  
“I don’t know what I would’ve done without you”  
“Oh it was nothing, but you have to tell me how it turns out. In fact…”, you grabbed a piece of paper, scrawled a number on it and handed it to the turtle “this is my number, text me if it works. And who knows, maybe you’ll get stuck again”  
“Maybe I will”


	4. Follow Him Into the Night

Donnie did get stuck again, in fact he seemed to be getting stuck a lot more frequently than he had been before. You knew he didn’t really need help, but you enjoyed his visits to the lab anyway. Slowly, the texts you received from Donnie asking to meet up became less and less specific with the problems. He was running out of excuses but he wasn’t going to let that stop him seeing you. Eventually, he simply sent you a text which said ‘hey, wanna meet up?’  
You replied in the affirmative and grabbed your jacket before heading off to the lab, where you found Donnie sat in the usual room. There was a pizza box beside him.  
“Hey D” you said with a smile, hopping up to sit on the counter next to him.  
“Hey, Y/N, I brought pizza”  
“I can see that” you said, scooping a slice up and taking a huge bite. Mouth still full, you couldn’t speak so just waved the familiar binder in your hand and made a series of mumbling noises.  
“Have you made some progress, then?”  
You nodded excitedly, opening the folder to the most recent page. On it was some formulas, some scribbled notes, but most notably there was a photo of a leaf with a small shoot growing out of it.  
“You solved it!” Donnie cried, grabbing the folder to take a closer look.  
“Not quite, but I’m almost there. The shoot keeps dying a few minutes after it grows” you explained, “but I’m nearly there”  
“If anyone can do it, it’s you” he said, putting the folder down and closing it “and when you do, you’ll go down in history”. You smiled, blushing. You’d never thought about going down in history, you just wanted to help people. Donnie pushed the book away from the two of you. “Well anyway, even us geniuses deserve a night off sometimes. Here, eat”, he passed you a slice of pizza and smiled as you devoured it.  
“Never mind us, whoever invented pizza is the greatest genius in history” you said, through a mouthful.  
“You’re not wrong” Donnie replied, taking one too. You munched in silence for a moment before an idea hit you. You glanced at Donnie a little cautiously, not entirely sure where the boundaries of your relationship lay.  
“Do you wanna watch a movie? I’ve got some on my laptop”  
Donnie considered for all of one second. “Yeah, ok. What d’you have in mind?”  
You didn’t have anything in mind, but that didn’t bother either of you. You pulled up one you hadn’t seen for a while. It wasn’t bad but it wasn’t good either. To be honest, you’d always considered it a perfect date film. It was good enough to provide distraction but neutral enough to not matter if you were paying attention. You grabbed a couple of cans of soda out of the staff fridge and ate pizza with a giant mutant turtle. No. You ate pizza with Donnie, your friend, the only person you’d ever really let into this secret part of your life. Somehow, that late night pizza and a movie changed everything. Somehow, and without either of you saying anything, the whole world shifted and when it had settled back into place everything was the same, but you weren’t. When the pizza was gone and the movie was finished you looked at Donatello, possibly the only person in the whole world who knew the real you, and you found yourself in love.  
He thanked you for a great evening and he left you. He always left you. Leaping away into the shadows and leaving you to go back to pretending you were normal, when all you wanted to do was follow him into the night.


	5. Understanding

**Notes for the Chapter:**

> I've been trying to work out where this chapter was going for ages but today I finally finished it.  
> Isn't it amazing what you can get done when putting off revision?

The night your wish came true was a cold one. Snow was falling from the sky in fat flakes, being whipped up by a fierce wind which howled through the gaps in your window frames and kept you awake. You tossed and turned and eventually gave up on sleep entirely, lying in the dark and registering the slowly growing headache the unrelenting wailing was giving you. That was when your phone vibrated on the bedside table, a short buzz indicating a text from Donnie.  
‘Hey, you ok? It’s pretty wild out there’  
‘I’m fine. Can’t sleep though, wind’s making a racket”  
There was a pause for a couple of minutes after that and you put your phone down, assuming he’d either fallen asleep or was satisfied that you were ok. However, a moment later your phone buzzed again.  
‘If it’s that bad, you could come sleep in the lair. No spare bed but we have a sofa, and it’s pretty quiet down here. As long as you don’t mind the slightly unpleasant journey here’  
You did not mind one bit. You just wanted to sleep somewhere quiet and safe. And you wanted to see Donnie. You always wanted to see Donnie. So you texted him back, accepting his offer gratefully.  
Donnie came to get you himself, travelling through the storm to get to your flat while you packed an overnight bag. The sight of him silhouetted against the sky as he waited for you to open the window was kind of eerie. When you finally unlatched the window and threw it open, the outside came rushing in along with the snow-covered turtle. Donnie was desperately trying to hide how cold he was but he was failing. You threw your arms around him.  
“Thanks for coming” you muttered into his neck.  
“No problem” he replied, trying not to show how his teeth were chattering, “you ready to go?”  
You pulled away from the hug and looked him up and down. “Do you want a hot drink first?”  
“Oh god yes” he replied, and you smiled.  
You put the kettle on and wrapped a blanket around your rescuer’s shoulders, making him a cup of hot chocolate.  
“Thanks for coming all this way for me, you didn’t have to”  
“Yeah, I did, that’s what friends are for”  
You smiled in return, really hoping your blush didn’t show through. Now that you weren’t talking, the sound of the wind howling through the window frames was clear.  
“Man, you weren’t lying ‘bout the wind making a racket, were you”  
“Nope, I keep telling my landlord that the windows are a wreck but he keeps ignoring me”  
You handed Donnie a mug of hot chocolate, marshmallows, cream and all. He accepted it silently and pulled it straight up to his lips, sucking in the heat like his life depended on it. Maybe it did, you weren’t sure. You felt bad for dragging him all the way out here in the middle of such awful weather, but Donnie would never let you apologise for it and you knew it. Hence the hot chocolate, a more material thank you.  
He emptied the mug quickly then put it on the side. “That is so much better, thanks”  
“No problem” you replied, smiling again. You couldn’t help but smile around him.  
“Shall we go then? It’s pretty late, you probably want some sleep”  
At them mention of sleep, your pure exhaustion hit again. He was right, it was far too late to be up on a night when you weren’t working.  
You met Donnie on the roof, not fancying your luck on the fire escape in this weather. It really was very cold. But Donnie made it warmer, helping you across rooftops because he claimed it was the quickest route. You weren’t entirely sure how you made it into the sewers, your hands were almost too cold to grip the ladder as you climbed down the manhole, despite wearing gloves. A short and smelly walk and you found yourself in an abandoned subway tunnel, but only for a little while before it opened up into an old station.  
The lair was exactly what you imagined it would be, it looked like it had been dreamed up by a teenage boy trying to play superhero.  
“What do you think?” he asked.  
“It’s perfect” you whispered in awe.  
Donnie would have offered to give you a tour but it was late and you needed sleep, even if you were clearly desperately trying to hide your yawns. “I’m glad you think so. Might I suggest we do the full tour in the morning? I don’t know about you but bed’s sounding pretty good to me”  
You nodded, eyelids dropping a little at the idea of sleep.  
“I’ll grab you a blanket, feel free to make yourself at home”  
Donnie provided blankets and pillows and showed you how to find the bathroom and kitchen. You said good night and he started to head off to bed but he turned back for a moment, one last glance to make sure you were ok, and then he just stopped. The sight of you in his home was weird, all too real somehow. It was different to seeing you in a lab. You were safe in your lab, you had the upper hand, but you’d walked straight into his home and for some reason that struck him as an enormous leap of trust.  
Because, in his mind, he was a monster. The turtles had battled this idea their whole lives, that they were monsters or at least would be seen as such by people. Trust was not something they were used to receiving. Then you noticed him staring. You smiled, you were always smiling it seemed to Donnie. He liked it.  
“What?” you asked.  
“What are you doing here?”  
Your smile lessened a little, confused. “Trying to get some sleep”  
“But what are you still doing here, with me?”  
His insecurities and fears were written all over his face. You could read that expression like a book.  
“You’re my friend. You’re my best friend”  
“Why? I just don’t understand why you gave me the chance to become that”, Donnie wanted to stop himself but the words wouldn’t stop coming. “I don’t understand why you didn’t leave. April didn’t leave because we helped her with the whole father being kidnapped thing, Casey didn’t leave because of April. But you didn’t have to stay, there was nothing holding you to us, to me, and yet here you are sleeping on my couch and I just don’t understand why”  
You thought about your answer for a moment. The look on his face told you this was no casual enquiry. This mattered to him.  
“Because I can’t leave. Every time I go outside I’m reminded of you. This city is you, Donnie. It’s weird and it’s full of secrets and I don’t understand it and I would never leave now that I’m here. There’s a darkness to you, Donatello. Pain and fear run through you like blood. And there’s something else too, some side of you that will never see the light. But I get that. There’s darkness in me too. But when I see your face the dark parts light up, you’re a scientific anomaly and I don’t understand it but in a far more honest sense I understand you. You’re like me, you’re more like me than anyone else will ever be. So, I’m not going to leave, I’m never going to leave. Not if it’s my choice”  
Donnie nodded once. He didn’t really know the words, so he didn’t try.  
Well, not quite. He knew some of the words needed.  
“I… understand you too”  
And because it was true, because you understood the way his mind worked like he understood yours you knew he’d read the hidden message in your words, and you read the hidden message behind his reply.  
'I love you too'


	6. Don't Dream of Normal

The storm passed before the night was over, leaving the city cold and grey but peaceful too. You awoke early, the cold air making its way under your blankets and forcing you from sleep. It took a moment to remember where you were, as is so often the case when you wake up somewhere new, but when you did you smiled and tried to bury yourself deeper into the warmth of your blankets, tucking your feet up to seal off the cold’s entry point.  
You were half-asleep, not quite unconscious but not really thinking either, when someone walked through the room you were in. You opened one eye just in time to see Donnie disappear into another room, catching a brief glimpse of what looked like some kind of lab beyond before the door closed behind him.  
With an immense effort, you shook off the remains of sleep and hauled yourself off the sofa, wrapping a blanket round your shoulders as you did so. You tiptoed over, unwilling to break the morning quiet of the lair, and tentatively pushed the door open, revealing a world of salvaged tech. In the few seconds before Donnie was alerted to your presence you took in all sorts, some of the things in the lab you recognised the purpose of but others were a complete mystery to you. In the corner, several experiments bubbled away, with half-filled notebooks covered in scribbled observations beside them. In another corner was what looked like some kind of half-built vehicle, although whether Donnie was repairing it or constructing it you couldn’t tell. The scientist himself was in the middle, tinkering with a significantly smaller machine, whatever it was appeared to be wrist-mounted but you couldn’t tell much more than that.  
You pushed the door open a little more to let yourself in, causing it to creak and alert Donatello to the fact he had a visitor. His head snapped up but he instantly relaxed when he saw you.  
“Y/N, good morning. Did you sleep well?”  
“Yes, very well. You’re up early”  
He shrugged. “I’m always up early, means I get more time to work without my brothers interrupting me”  
“When do you get time to sleep?” you asked. He shrugged again.  
“I’ve adapted to run on very little”  
You simply raised an eyebrow in reply.  
“I have!” he protested.  
“Sure, if you say so. Well I don’t know about you but I fancy some breakfast. Do you have eggs?”  
“Yeah, in the fridge, but I can’t guarantee anything else you want will be in a sensible place, Mikey has the kitchen organised to his own ridiculous system”  
“Well, then I guess you’ll just have to come and help me, it’ll be like a breakfast date”  
“A breakfast… date?”  
You brushed past your use of the word ‘date’ easily, trying to ignore the awkwardness. “Come on, doofus, I’m hungry”  
“Can I at least finish this first?” he pleaded, waving the mechanism he was working on. You eyed it sceptically.  
“What is it?”  
“It’s a wrist-mounted web shooter”  
You desperately tried to hold in your laughter. “You mean like Spiderman?”  
“Don’t laugh. It’s not for swinging between buildings, it’s for apprehending people. You shoot the fluid inside”- he held up the device and aimed at an empty wall, activating the mechanism and sending a large splat of what can be best described as stuff shooting out – “and blam! They can’t run anymore”  
“Alright, Spidey, very impressive. Now come on, even Peter Parker needs his eggs on toast”  
You took the device from his hand and put it on the table, taking his hand and leading him out of the lab.

Donnie tried to explain where to find the various ingredients you wanted, but it quickly became clear that things were going to go a lot quicker if you cooked and he found the ingredients for you. You watched him pull a pan out of a top cupboard that was otherwise full of spices.  
“What the hell is going on in Mikey’s head?” you wondered aloud, whisking together egg and milk in a bowl.  
“Mikey’s got a very special way of thinking” Donnie replied, clambering off the worktop he’d scaled to reach the cupboard.  
“You can say that again”  
“You’d be surprised how often it helps, actually. My brothers and I end up in so many ridiculous situations that sometimes some truly unconventional thought is exactly what we need”  
“I don’t think I want to imagine what kind of situation requires thought like that” you said, grinning and accepting the pan. Donnie’s return smile was a little grim.  
“Sometimes I wish I couldn’t imagine it. Sometimes I wish our lives could just be a little closer to normal”  
Your grin faded and you put the bowl down, putting a hand on his shoulder. “I don’t know much about your life, but I do know that normal is not your thing. If you were normal, Donnie, you wouldn’t have the chance to create the things you do. You’re the most brilliant person I’ve ever met, it would be a shame to waste that on normality”  
“You’re normal, and yet you’ve got access to a whole lab”  
“Only illegally at night, during the day I do as I’m told. Down here, you have your own lab, and complete freedom to create what you please. If I had that, then I’d have made the breakthrough I’m so desperately chasing years ago. Don’t dream of normal, Donnie, you are a wonder and a miracle and you are perfect exactly as you are”  
You placed a gentle kiss on his cheek and pulled away in time to see the bright blush burning on his cheeks and your hand strayed down from his shoulder to momentarily tangle with his fingers and squeeze before moving away.  
“Come on, let’s have some breakfast. I have to be at work today and I need to go home first to get my lab clothes. See? That’s what normal is, rushing breakfast so that I can go to work rather than spend the day with my best friend”  
“Ok, that bit doesn’t sound so fun”  
“Exactly” you said, pouring the egg mixture into the pan.


	7. Consequences

Your trip to the lair had inspired you, somewhat, and you headed to work with a spring in your step and a firm belief that soon you would crack the problem you’d been working on. You would be the one to unlock the secrets of making organic material regenerate quickly and safely. You could save countless lives. You’d publish your work and dedicate it to Donnie, no one need know who the mysterious Donatello was and it would be a nice nod towards him.  
You’d be showered with praise, given your own lab for research. Maybe you could even have Donnie come and help you!  
You worked yourself up into a frenzy of excitement as you approached the lab. It didn’t last.  
One look at your place of work and you knew something was very, very wrong.  
There were police everywhere, the windows were all smashed and somewhere something was burning. Most concerningly, painted in large red letters on the side of the building were the words ‘Give up the mutants’  
There was only one thing that could mean. They knew Donnie had been coming here.  
Horrified, you walked up to the nearest police officer. “What happened?” you asked. The woman looked at your white lab coat and made the correct assumption that you worked there.  
“You’re one of the lab assistants, are you?”  
You nodded and gave your name. “What happened?” you asked again.  
“Someone, or rather a group of someones, trashed the lab some time last night and left that message. I’ll need you to stick around and answer a few questions, standard procedure, all of the staff will be interviewed”  
You stayed for a couple of hours, lied to the police by claiming to know nothing of what this could be about, and then went home. You knew exactly what mutants were being referred to.  
This was all your fault, for inviting Donnie to the lab so often. They’d tracked him to there and realised it was one of the staff he was meeting.  
A huge wave of guilt surged over you, but before you could get any further into your pit of misery, your phone rang. It was Donnie.  
“Y/N! It’s all over the news! What happened?” he asked.  
“What?”  
“The lab, Y/N”  
“Oh, that. It’s my fault, Donnie! It’s all my fault!”  
“Woah, hold on, it’s not your fault”  
“They tracked you to the lab because I kept inviting you there!”  
“Y/N, listen to me, this is nothing to do with you. I’m the one they want, I was careless, you did nothing”  
“But-“  
“I’m coming over. I’ll be there soon, ok”  
You nodded but realised he couldn’t see that so managed to force out a small “Ok” past the lump in your throat.  
Donnie didn’t waste any time, soon he was knocking on your window and you flung it open, nearly knocking him off the fire escape in the process. You couldn’t manage to care as you threw yourself into his arms.  
“It’s all my fault, Donnie!”  
He wrapped his arms around you and brought you back inside, closing the window and the curtains after he’d placed you on the sofa. Once the world was shut out he came and sat next to you.  
“I just… Things were going so well. And now I’m realising that all this time I was putting everyone at the lab in danger, and I was putting you in danger and-“  
“Y/N, you haven’t done any of this. It was my fault for not being more careful. I should have realised they might find out. It’s lucky no one was hurt. The good news is, I don’t think they know it’s you I’ve been meeting yet”  
“You’re not going to stop visiting, are you?” you asked, fear in your voice.  
“I don’t know. Maybe for a while”  
“No!”  
“To keep you safe”  
“I don’t wanna be safe, I wanna be with you!”  
“Just for a bit, to put them off the scent”, he could see the next protest forming in your throat so but a finger on your lips. “You’ll see me again”  
“When?”  
“In a few weeks, once I can be sure they’ve let the lab thing go”  
“That’s too long”  
“Nah, it’ll be no time at all” he said, trying to make his voice sound light and uncaring, but the pain in his eyes was all too clear. He took a deep breath and stood up, and you knew he was leaving.  
“Do you have to go just yet?” you begged, leaping up and grabbing his hand.  
“I’m afraid so”  
“But-“, you could feel the panic rising in you, the idea that you would never see him again, and there was only one thing you could think to do. You leant forward and kissed him, stealing away any words he might have been about to say for one beautifully drawn out moment, before you pulled away. “Now you have to come back” you whispered.  
His nod was almost too small to see. “I will, I promise. Once it’s safe”  
You barely registered as he opened the window and disappeared. Leaving you alone.


	8. Discovery

Ok, so Donnie’s ban on communication was technically still in effect, but this was big news. Like, really big. Like, change the world big. And you had to tell him. You just had to.  
So you left your flat, forged your way through the snow that was piling up outside, and slipped into the sewer.  
Donnie was in his lab and he was, understandably not expecting to see you, so when his door burst open he was instantly on edge, spinning away from the machine he was tinkering with, eyes wide.  
“Donnie!”  
“Y/N? what the shell are you doing here?” he asked, unable to feel anything other than surprise as the figure of his girlfriend flew in like a whirlwind and barrelled into him.  
“I know you said I couldn’t visit or talk to you, but I missed you and I just had to show you! It’s incredible!” you burbled as you clung to him, he put the tool in his hand down and wrapped his arms around you briefly before pulling away.  
“You’re not supposed to be here” he said, trying to be annoyed at you for breaking his ban but unable to keep the joy off his face.  
“I know, I know, but I had to show you”  
“Show me what?”  
You swung your bag off your shoulder, producing your ever-present binder, along with a bottle of liquid and a small plant. Donnie put the pieces together.  
“Wait, did you do it? Did you actually manage it?” he asked, following you to a table where you dumped the binder down, tearing a small leaf off the plant and placing it on the desk.  
“Watch” you said, carefully pouring a single drop of liquid onto the leaf. It did nothing for a moment, then it fizzed a little, and then, slowly but surely, the leaf began to sprout. Within a few minutes the small plant had stabilised at a few centimetres tall, and apparently healthy.  
“I did it this morning, I’ve tried it on various types of plant life and all of them have turned out healthy. My flat looks like a mini jungle” you said, beaming from ear to ear. Donnie looked from the small plant on his desk to you, then burst out laughing, scooping you up in his arms.  
“You did it! You’re a genius!” he cried, swinging you around. “This is gonna change the world, y’know”  
“I know” you said, trying to find your balance as Donnie placed you back down. Then your grin faded a little. “The only thing is, Donnie, if I’m going to make this work I can’t do it here”  
That stopped everything in its tracks. “What do you mean?”  
“This discovery changes everything. With just a little work I think it can be adapted to promote healing in animal cells, in humans. I can’t do that here, I have to take it somewhere else, somewhere with more funding and better equipment, where there’s no chance of my work getting destroyed by gangs who want my friends”  
“Wait, so you’re leaving?”, Donnie couldn’t comprehend what that meant. You’d become such a massive part of his world that not having you nearby was unthinkable. Your face showed reluctance.  
“I don’t want to. But I can help so many people with this, Donnie, I don’t have a choice”  
You were right, of course. If there was one thing the two of you understood it was that the science came first, the people who could be helped came first. That didn’t make it any easier.  
“When are you leaving?”  
“I’m not sure yet. I’ve got to write this up, reach out to a few people. Could be a few weeks, could be a few days”  
You could see the despair forming on his face, the protest preparing itself on his tongue. You stopped him with a kiss, grabbing his arms and dragging his lips onto yours. “I’ll still visit, Donnie, I promise. And we can text and video chat and-”  
“But you won’t be here” he replied, wrapping his arms around you, feeling how solid and real you were, “I won’t be able to hold you and feel you and know that you’re with me”  
You had nothing to make that better. “No, I won’t be”, you nuzzled your face into the side of his neck. “But I have to do this, Donnie. I have to do what I can to help people. And think of my career! If I do this, if I succeed then I’ll be flung into a whole new scientific circle. Scientists, Donnie, people at the forefront of research. Maybe I can introduce you to them, if anyone can accept you it’s them”  
Donnie shook his head. “No, Y/N, my place is here, in the shadows. Just promise you’ll come back”  
“As often as I can, I promise”  
“Well we still have some time together. We might as well celebrate, after all, it’s not every day you make a world changing scientific discovery. Come on, I’ll get my brothers together, we can make it a party”  
You smiled and nodded. “Yeah, that sounds good”  
You did your best to forget all the negatives for the evening, partying with your friends and never once leaving Donnie’s side. It would be tough, but he was here for you, he always would be.


	9. The Note

She left, just like she’d said she would. It took her 2 weeks to sort it all out. Donnie didn’t say anything about it to his brothers, but they knew enough to put it together. Enough to work out that the girl who kept taking their brother’s time and making him happy was gone. Enough to work out that it wasn’t as simple as her breaking up with him, not that Donnie had ever confirmed their guesses that a relationship even existed. He was broken, but not broken-hearted.  
Donnie let her go, it was just another sacrifice among many he’d made for the good of the human race. He kissed her goodbye and she promised she’d be back soon, and then she was gone. He dragged his painful heart back to the lair, back to the lab. He slumped at his desk and simply sat there for a moment, too emotionally drained to do anything else.  
He sat there for a whole 15 minutes before he noticed the note. It was a sheet of folded paper with his name written on it in her familiar handwriting. He grabbed at it like that piece of paper was all that could keep him alive, unfolding it madly and staring at the words written there.  
‘Donnie’ he read, ‘Thank you for opening my eyes and showing me a whole new world. I could never say it to your face before, was too afraid, but I am in love with you completely and utterly’  
She had signed her name at the bottom.  
Donnie read that note far more times than he’d bother counting, making sure he understood it and wasn’t just seeing what he wanted to.  
Then he took out his phone, selected her number, and called it. She answered after only one ring.  
“Donnie, I haven’t even been gone an hour” he heard her voice say, and, even though he couldn’t see her, he knew she was grinning. He didn’t bother with a greeting, there was something far more important that he needed to say.  
“I love you too”  
There was a moment of silence, then her voice again. “I rather hoped you might”

 

That was another thing Donnie never told his brothers about. He locked the note away somewhere safe and from that day onwards he fought harder than he ever had before. Yes, it wasn’t just the attacks on her lab that had sent her away, but that was one contributing factor, and if he could just take down Shredder once and for all then maybe she’d return and he could look her in the eyes every day and tell her that he loved her back.


End file.
